Anyone who turned on a car radio 50 years ago could count on routinely hearing something we almost never hear on the radio today: news about labor unions.

Unions made news back in those days all the time. The news breaks that radio stations then carried every hour were always updating the status of major contract negotiations in America’s biggest industries, everything from auto to trucking.

Those negotiations mattered. They involved millions of workers across the nation. And the contracts that emerged out of these negotiations didn’t just impact the union workers or the new agreements covered. They impacted nonunion workplaces as well.

All throughout the mid 20th century, for instance, the giant retailer Sears kept itself largely nonunion by trying to mirror the wages and benefits that nearby unions had negotiated.

Companies like Sears had little wiggle room. In many major metro areas outside the South, unions represented half or more of local workers. To compete for labor in these markets, nonunion employers couldn’t afford to ignore the gains unions were achieving.

And unions were achieving plenty. In the two decades right after World War II, the real wages of American workers doubled. The United States, over the course of these years, became fundamentally more equal, and unions played a huge role in forging this greater equality.

How regularly? In 1967, the nation experienced 381 separate “work stoppages” that involved at least 1,000 workers. Nearly 2.2 million workers took part in these walkouts. Hundreds of thousands more participated in strikes at smaller workplaces.

Some perspective on these numbers: In 2016, the U.S. Labor Department’s Bureau of Labor Statistics reported earlier this year, the nation saw only 15 strikes that involved at least 1,000 workers. Over the last decade, we’ve seen just 143 such strikes. In the decade that began back in 1967, by contrast, walkouts at large workplaces took place 20 times more often.

Top executives at major U.S. corporations today simply face far less pressure than their predecessors faced a half-century ago. Our contemporary CEOs operate in what has largely become — to use the phrase conservatives so enjoy using — a “union-free” environment.

The real “freedom” in this environment extends only to top execs. They can freely push down on worker wages, water down benefits, and even eliminate jobs and pensions. And best of all — for them — these executives can pay themselves much, much more than executives years ago ever dreamt they could make.

The AFL-CIO, America’s trade union center, last week released the latest annual figures on average CEO and worker pay. Major corporate executives in 2016, labor’s PayWatch site details, took home 347 times more than average American workers. A half-century ago, in the mid-20th century, top CEOs in the United States seldom made more than 30 times what workers took home.

Back then, in the 1950s and 1960s, over a third of private-sector workers nationwide belonged to unions. Today less than 7 percent of private-sector workers carry union cards.

This steep crash in union representation, political scientist Andrew Kolin makes clear in his new book on the history of labor repression in the United States, didn’t just happen. That crash reflects years of corporate maneuvering to deny working people their right to organize and bargain collectively.

In the past, Kolin also makes clear, working people faced similar — and even worse — attacks on their basic rights. But they persevered and eventually ushered in the more equal United States of the mid 20th century. For that more equal United States to return, we will need another labor comeback.